Five children belonging to two families drowned while picking up cashews in Dong Nai Province Saturday.

The tragic accident happened when one of the children slipped into a drain and others tried to help.

The children, including two 11-year-old girls and their two younger brothers and sister, were spending their after-class time picking cashews that dropped at local fields.

Three of the children, Nguyen Thi Thao Vy, 11, Nguyen Thi Yen Nhi, 9, and Nguyen Trung Hau, 7, were from one family and two others, Pham Thi Phuong Uyen, 11, and her brother Pham Tuan Hiep, 8, from another.

Police said the children drowned in an unfenced drain around two meters wide and up to two meters deep, according to a Tuoi Tre newspaper report.

Their bodies were recovered after Nguyen Thi Ngoc Anh, the younger sister of three victims Vy, Nhi and Hau ran back to the residential area around 800 meters away, crying for help.

"When Vy slipped and fell down, Uyen jumped down to save her, and then Hiep, Nhi and Hau. But none of them could swim," said Anh, the only survivor and now the only child left in her family.

Pham Duc Hoa, the father of Uyen and Hiep, said Uyen and the children were planning to sell the cashew nuts they picked to buy a cake for her birthday on Sunday. It would have been the very first birthday cake she had, to celebrate the end of primary school.

"Several days ago, she asked me to invite some friends over for her birthday but I did not have money for that. So she asked her brother and the nearby children to pick cashews," Hoa said, cited by Tuoi Tre.

"It's all my fault. I could not give her a cake, and my children had to work for it, only to die."

Local authorities and Red Cross have helped the families with five coffins and ex gratia payments of VND25 million (US$1,200).